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1.
Magnetization measurements in the (Dy
x
Y1−x
)Fe2 intermetallic compounds show evidence of blocking of domain wall motion. This effect is a function of concentrationx. The direction of magnetization is also dependent on the Dy concentration. We have used the Mossbauer spectroscopy of57Fe to verify the direction of magnetization in the series as a function ofx and temperature. The results show that this change in easy direction occurs at higher temperatures than those where the blocking
is detected through DC magnetization measurements.
supported by RHAE/SCT. 相似文献
2.
Cr1-x
Fe
x
and Mn1-x
Fe
x
films were prepared at room temperature by thermal coevaporation at a deposition rate of about 25 Å/min. It was found that an amorphous phase can be obtained for Cr1-x
Fe
x
(0.25<x<0.60) films, while a metastable-Mn-type phase was observed for Mn1-x
Fe
x
(x<0.70) films. The influence of the structure on the magnetic properties has been studied. The amorphization ability of the two systems was discussed in terms of thermodynamic considerations. 相似文献
3.
E. Baggio-Saitovitch R. B. Scorzelli I. Souza Azevedo C. Diaz-Aguila 《Hyperfine Interactions》1994,83(1):425-429
La2–x
Ca
x
Cu0.99Fe0.01O4–y
samples with 0.00 x 0.30 were studied by X-ray diffraction and Mössbauer spectroscopy after heat treatment under different atmospheres (air, oxygen and helium). The variation of the relative population and the hyperfine interactions of the sites as well as the change in the lattice parameters were obtained.On leave from National Center for Scientific Research, PO Box 6990, Havana, Cuba. 相似文献
4.
W. T. Herrera C. Rojas-Ayala I. S. Din��la E. C. Passamani M. Kraken J. Engelke E. Baggio-Saitovitch F. J. Litterst 《Hyperfine Interactions》2011,203(1-3):143-147
Films of ytterbium doped with iron (0.3?C1.6 at.% Fe) have been prepared by co-deposition of atomic beams of the elements onto Kapton substrates under high vacuum. Iron is immiscible in ytterbium and various iron species are expected to occur. XRD reveals a mixture of fcc and hcp ytterbium. The Mössbauer spectra are interpreted with contributions from monomeric iron on interstitial sites, two types of neighboring substitutional iron aggregates and two types of clusters formed upon diffusion. The present data supplement earlier data obtained for 0.5 and 5 at.% Fe. There is no systematic correlation of cluster formation with increasing iron concentration. There are indications that clusters are formed more easily for thin films. We conclude that cluster formation occurs mainly on the film surface and is limited by the slow diffusion from inside films. 相似文献
5.
J. Quispe-Marcatoma C. Rojas-Ayala C. V. Landauro M. A. de Sousa F. Pelegrini M. Taquire V. A. Pe?a Rodriguez E. M. Baggio-Saitovitch 《Hyperfine Interactions》2011,199(1-3):1-8
We have measured several Q values at JYFLTRAP for superallowed ?? decays that contribute to testing the Standard Model and candidate nuclei that one could use for the search of neutrinoless double-?? decay. These results play important roles in the research of fundamental physics that have scopes beyond Standard Model. 相似文献
6.
FeSiB Amorphous Alloy Prepared by Mechano-Synthesis 总被引:2,自引:0,他引:2
J. Quispe Marcatoma V. A. Peña Rodríguez E. M. Baggio-Saitovitch 《Hyperfine Interactions》2001,134(1):207-212
In this work we show that mechano-synthesis is a good method to prepare the FeSiB amorphous alloy starting from Fe, Si, B pure elements with relative atomic composition of 75, 15 and 10%, respectively. We have used a high-energy ball-milling system keeping the material under an Ar atmosphere. The evolution of the microstructure inside the grains is followed by X-ray diffraction and Mössbauer spectroscopy at room temperature. The dependence of crystalline size, lattice parameter and hyperfine parameters on milling time is discussed. Our results show that the milled samples obtained after 10 h of milling contained a bcc structure in the amorphous matrix. After 19 h of milling the sample became fully amorphous. 相似文献
7.
对新概念指导下而设计的(La1-xSrx)2Cu1-xSnxO4超导体进行了119SnM(o)ssbauer谱研究.对不同掺杂量样品的系统研究表明,M(o)ssbauer谱实验结果进一步证实了Sn以Sn4+价态存在并占据Cu晶位,不存在占据La晶位的Sn2+离子. Sn4+离子附近的局域晶格畸变较小,但是随Sn掺杂量有增加趋势.在对La2CuO4母体进行Sr和Sn同时掺杂所引入的载流子对超导电性的影响存在新的机制.在新的额外氧机制下,讨论了Sn掺杂所导致的额外氧对超导电性的影响. 相似文献
8.
E. Baggio-Saitovitch 《Hyperfine Interactions》1991,66(1-4):231-247
The information obtained from57Fe Mössbauer spectroscopy for samples of YBa2(Cu1?x Fe x )3O7±δ covering a large range ofx values is discussed concerning the structural aspects, iron site occupation, local oxygen coordination, magnetic ordering, sensitivity to oxygen content and aging effects. 相似文献
9.
Ion implantation of57Fe in YBaCuO pellets with different oxygen contents was tested for three parameters: total fluence, energy of the Fe ions
and target temperature. The CEMS spectra obtained at room temperature are complex and we present here the analysis obtained
for distinct symmetric doublets. The results are discussed on the basis of iron species present in sintered Fe: YBaCuO samples
and spurious phases like Y2BaCuO5. 相似文献
10.